Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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sulphuric acid : H2SO4
sodium hypophosphite : NaH2PO2
potassium bromate : KBrO3
Class:
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elem=P,Br
redox
Summary:
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A mix of finely powdered sodium hypophosphite and potassium bromate forms an
energetic mix which can easily be ignited.
Description:
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Take some sodium phosphite and grind this such that a fine powder is obtained.
Only use a small amount of solid (e.g. a small spatula full of solid).
In a SEPARATE dish put a similar amount of solid potassium bromate and also
grind this such that a fine powder is obtained.
Add the two solids to each other in a petri dish and carefully mix them by
rocking the petri dish forwards and backwards such that the powders are mixed
thoroughly.
Put some of the powder on the tip of a metal spatula and keep this in the flame
of a small alcohol burner: The mix quickly ignites and burns very fast with an
orange flame.
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Collect the remaining amount of powder near the rim of the petri dish, put all
of it in a small pile and add a single drop of 20% sulphuric acid to the solid:
The part of the solid which is wetted at first does not seem to change, but
after a few tens of seconds it turns yellow, then orange. Suddenly, the
reaction goes very violently, bromine vapor is released and remains of dry
powder ignite with an orange flame.